In most dispensers for sterile liquids in the past it has been necessary to add preservatives to the liquid to render innocuous any contaminates that find their way into the dispensing container or discharge passages. Because such preservatives have caused irritations of tissues, there has been a desire to eliminate them and, hence, a need for a dispensing system designed to keep contaminates out.
In my earlier patent U.S. Pat. No. 5,370,313 issued Dec. 6, 1994, I disclosed a sterile liquid dispenser in the form of a pocket-sized container made to dispense liquid in a sterile way. Because the dispenser is especially designed with an effective tip seal, it makes it possible for the first time to provide a handy dispenser for eye care liquids, for instance, without the need for blending into the treatment solution a preservative. This is more fully described in my earlier patent, and the entire earlier disclosure is incorporated hereinto by reference.
My earlier invention in patent U.S. Pat. No. 5,370,313 contemplated a "bottle under pressure" with a tip seal. The "bottle under pressure" is disclosed as a container enclosing, in addition to the product, a discharge assistant, such as a propellant generating pressure, a compressed gas or a bag under external pressure. While a plastic squeeze bottle, when squeezed, is clearly a "bottle under pressure", heretofore my earlier invention of patent U.S. Pat. No. 5,370,313 has not been used with squeeze bottles. This is because when a squeeze bottle is released there has been an inevitable "suck back" of air through the discharge passage. If such "suck back" is prior to seating of the tip seal, it effects the "inhaling" of contaminates into the outlet to reside and grow, making an unacceptable situation for liquids required to be sterile.
Because, as described in my earlier patent, the optical industry has customarily packaged eye treating liquids in squeeze bottles, and the public is used to such packaging, there is a need for a squeeze bottle dispenser for sterile liquids. It is to this need that the present invention is directed.